Microstructural analysis of hybrid materials composed of nepheline crystals and a glass matrix fabricated from coal bottom ash

作者：Jang Seokjoo; Kang Seunggu^*

来源：Journal of Ceramic Processing Research, 2009, 10: S59-S63.

• Coal bottom ash
• Surface crystallization
• Glass-ceramics
• TiO(2)
• nepheline
• Avrami
• Activation energy

Hybrid materials composed of a glass matrix and nepheline(NaAlSiO(4)) crystals were fabricated by heat treating a glass obtained from a batch of coal bottom ash produced at thermal power plant, with fluxing agents, Li(2)O and Na(2)O, and a nucleation agent TiO(2). The dependence of physical properties of the hybrid materials upon their microstructures was analyzed. The nucleation and crystallization temperatures for the nepheline, the major crystalline phase, were determined by comprehensive differential thermal analysis (DTA) with a varying heating rate 5-20 K.minute(-1) and X-ray diffraction (XRD) pattern results. The growth behavior of nepheline crystals in the hybrid materials were studied and the effect of the activation energy for nucleation, and Avrami constant calculated by a non-isothermal method on the physical properties were analyzed. A higher activation energy for crystallization and a smaller Avrami constant were favorable for one-dimensional crystal growth on the surface of a specimen. The addition of TiO(2) suppressed the surface crystallization of nepheline crystals, and the internal crystallization was enhanced to increase the microhardness.

• 出版日期2009-10